The present invention relates to an improvement in a device for detecting the leakage of vapors of liquid hydrocarbons such as petroleum, gasoline or heavy oil, a variety of organic solvents such as carbon tetrachloride or methylethylketone (MEK), or a variety of liquids having a high vapor pressure such as MEK, gasoline or ammonia, into or onto the water which, for example, surrounds an oil storage tank.
The present applicant has previously proposed a liquid detecting element as disclosed in Japanese Patent Laid Open Publication No. 53-145697. In that case, the liquid detecting element has a drawback in that its detecting sensitivity is extremely decreased with the passage of days in situations in which it is positioned in water to detect the leakage of liquid into or onto the water. This decrease is caused by the adhesion to or growth onto the device of extraneous matter in the water contents, and these extraneous substances frequently have to be removed from the surface of the detecting element which takes a considerable amount of time for maintenance and must be undertaken with prior art devices so that the original detecting sensitivity may be recovered.
In view of the foregoing, it is an object of the present invention to provide a leakage detecting device for which the maintenance of removal of the extraneous substances in water is substantially eliminated.